Description of the component:
The 400 mm half-shell represents one half of a satellite tank made of titanium. After additive manufacturing, the inside is machined while the outside remains unmachined. Two half-shells are joined together using TIG welding and then wrapped in CFRP. The tanks will later contain xenon or helium.
The challenge:
Until 2020, such rotationally symmetrical geometries at MT Aerospace were still created from forgings or milled from solid material: With a material removal rate of 98%, this was not a very economical process. In addition, the long delivery times for forged parts meant that it took up to twelve months before a tank could be completed. As cost pressure in the aerospace industry has also risen sharply in recent years, it was time to develop a new solution.
Solution:
By adding laser deposition welding (DED) to the technology portfolio, the company's engineers were able to print such a half-shell in less than five hours, while making almost optimal use of the source material in powder form. DED stands for "Directed Energy Deposition" and describes the welding of metal powder using a laser source. The machine operates in five-axis mode, just like conventional CNC machining/milling machines, except that additive manufacturing is used here. DED produces higher deposition rates than the PBF-M process, but is particularly suitable for rotationally symmetrical components. Through final non-destructive testing procedures, MT Aerospace was able to ensure that the tank can withstand all loads and that the process is suitable for later use.
Conclusion:
By using additive technology, the delivery time for a satellite tank was reduced from around twelve months to three months. What's more, production is around 20 % cheaper. This successful first project has enabled MT Aerospace to identify further components that will be produced additively rather than conventionally in future. DED has therefore proven to be a scalable process.